I'm not sure if this book was persuasive — at least in one aspect. Sure, each short chapter features a principle of persuasion, explained and amplified with examples and anecdotes. And the idea behind each one is lucidly presented, logical and — for the most part -- surprisingly obvious, meaning that few of the ''50 scientifically proven ways to be persuasive'' are terribly counterintuitive; in fact, each one makes sense.

For example, in one chapter, they discuss how the brilliant copywriter Colleen Szot made a slight change to an infomercial and saw response rates skyrocket.

Instead of telling prospective customers that ''operators are waiting, please call now,'' which invokes an image of bored employees staring skeptically at their idle telephones,' Szot's script says ''if operators are busy, please call again,'' to which the authors add, "Now consider how your perception of the popularity of the product would change when you heard the phrase `if operators are busy, please call again.' Instead of those bored, inactive representatives, you're probably imagining operators going from phone call to phone call without a break. In the case of the modified 'if operators are busy, please call again' line, home viewers followed their perceptions of others' actions, even though those others were completely anonymous. After all, 'if the phone lines are busy, then other people like me who are also watching this infomercial are calling, too.' ''

It's a subtle but powerful distinction, and if it defies credulity, it's only because you may not have considered that we — consciously or otherwise — tend to seek the security of like-minded people when making a decision. You may not think that is the case, especially if you are a bold, iconoclastic, freethinking individual, but according to the authors, their research indicates that most people do what most people do.

The other 49 principles are equally applicable to the masses; after all, though there are rugged (or refined) individualists among us, this book is focused on the tendencies of groups, though exceptions are inevitable. But the idea here is not to use the information and methods for funky or malevolent purposes. In fact, the authors repeatedly warn that any claims or statements used to advance ideas or elicit actions must be truthful and correct. And the book's brief epilogue recounts a cautionary tale involving the abuse of these methods.

Following that, they include an interesting set of testimonials from professionals who've employed 34 of their 50 ways. Not coincidentally, it's an ideal demonstration of the power of authority to convince readers of their efficacy.

But what about this book was unpersuasive? For me, it was the participation of Robert Cialdini, whose name is twice the size of the others on the dust jacket. My sense is that his ''authorship'' possibly consisted of reviewing the text, which was most certainly inspired by his earlier work, specifically his classic Influence: Science and Practice, currently in its fifth edition. Though ''Yes!'' is a solid, useful and very readable look at the subject, it lacks the good professor's voice — though you may be persuaded otherwise.